Filter apparatus for ostium of left atrial appendage

ABSTRACT

Apparatus for permanent placement across an ostium of a left atrial appendage in a patient, which includes a filtering membrane configured to extend across the ostium of the left atrial appendage. The filtering membrane has a permeable structure which allows blood to flow through but substantially inhibits thrombus from passing therethrough. The apparatus also includes a support structure comprising a plurality of fingers which are radially outwardly expandable with respect to a longitudinal axis to permanently engage the interior wall of the left atrial appendage, wherein the filtering membrane is attached to the support structure extending across the ostium of the left atrial appendage.

[0001] This application is a continuation of application Ser. No.09/697,628, filed Oct. 26, 2000, which is a continuation-in-part ofapplication Ser. No. 09/614,091, filed Jul. 11, 2000, which is acontinuation-in-part of application Ser. No. 09/428,008, filed Oct. 27,1999, (now U.S. Pat. No. 6,551,303) all of which are incorporated byreference in their entirety herein. This application also claims thebenefit of U.S. provisional application No. 60/196,454, filed Apr. 11,2000, U.S. provisional application No. 60/206,967, filed May 25, 2000,U.S. provisional application No. 60/209,511, filed Jun. 5, 2000, andU.S. provisional application No. 60/211,896, filed Jun. 16, 2000, all ofwhich are incorporated by reference in their entirety herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a membrane structure applied to oracross the ostium of an atrial appendage for filtering blood between anatrium of the heart and the associated atrial appendage or appendages toprevent a thrombus from leaving the atrial appendage while allowingblood flow through the membrane.

[0004] 2. Description of the Related Art

[0005] There are a number of heart diseases (e.g., coronary arterydisease, mitral valve disease) that have various adverse effects on theheart. An adverse effect of certain cardiac diseases, such as mitralvalve disease, is atrial (or auricular) fibrillation. Atrialfibrillation may result in pooling of blood in the left atrialappendage. Blood pooling may also be spontaneous. When blood pools inthe atrial appendage, blood clots can form and accumulate therein, buildupon themselves, and propagate out from the atrial appendage into theatrium. These blood clots can then enter the systemic or pulmonarycirculations and cause serious problems if they migrate from the atrialappendage and become free in the blood stream and embolize distally intothe arterial system. Similar problems also occur when a blood clotextending from an atrial appendage into an atrium breaks off and entersthe blood supply. Since blood from the left atrium and ventricle supplythe heart and brain, blood clots from the atrial appendages can obstructblood flow therein causing heart attacks, strokes or other organischemia. It is therefore necessary to find a means of preventing bloodclots from forming in the atrial appendages and to prevent these bloodclots, once formed, from leaving the atrial appendages to the heart,lungs, brain or other circulations of the patient which can cause heartattacks or strokes or other organ ischemia.

[0006] U.S. Pat. No. 5,865,791 relates to the reduction of regions ofblood stasis and ultimately thrombus formation in such regions,particularly in the atrial appendages of patients with atrialfibrillation. More specifically, the '791 patent relates to proceduresand devices for affixing the atrial appendages in an orientation thatprevents subsequent formation of thrombus. In the '791 patent, theappendage is removed from the atrium by pulling on it and by putting aloop around it to form a sack of the atrial appendage and then cuttingit off from the rest of the heart.

[0007] U.S. Pat. No. 5,306,234 relates to a method for surgicallyclosing the passage between the atrium and the atrial appendage orsevering the atrial appendage.

[0008] Other methods of treatment include surgically removing the atrialappendages to prevent blood stasis in the atrial appendages.

SUMMARY OF THE INVENTION

[0009] The invention provides a filtering membrane that allows blood topass therethrough while substantially preventing blood clots formed inthe atrial appendages from exiting therefrom. Such clots may cause heartattacks, strokes and other embolic events if allowed to leave the atrialappendage and enter the bloodstream.

[0010] The filtering membrane is permanently positioned across theostium of the atrial appendage by a support structure attached to thefiltering membrane. The filtering membrane filters blood flowing betweenthe atrium and the left atrial appendage and effectively isolates bloodclots from leaving the atrial appendage and entering the atrium. It maybe larger than the ostium of the appendage, and extend over an arealarger than the appendage ostium. It is percutaneously delivered to theostium of the atrial appendage by a catheter and then may be expandedfor positioning across or over the ostium and has a means to secure thefiltering membrane across or over the ostium.

[0011] The filtering membrane itself is permeable to permit blood flowacross the membrane. By allowing the such blood flow across themembrane, the porous structure minimizes any pressure gradient betweenthe atrial appendage and the atrium in a controlled manner. The porousfiltering membrane may eventually become infiltrated with cells. Thepermeable filtering membrane allows such tissue growth which may beginalong the outer periphery of the structure. Such tissue growth minimizesuncontrolled leakage about the periphery of the filtering membrane andmay assist in attachment of the filtering membrane to the ostium orsurrounding tissue.

[0012] There are many means for fixing the filtering membrane inposition across the ostium of the atrial appendage. The supportstructure for the filtering membrane may have a means for self-centeringthe filtering membrane over the appendage ostium. The filtering membranemay be glued to the wall of the atrial appendage adjacent the ostium, orthe support structure may have wires, barbs, prongs or other methods offixation which pass through the ostium and extend into or through theatrial appendage and which permanently engage an interior wall thereof.Alternatively, an anchor in the wall of the atrial appendage may betethered to the filtering membrane for holding the filtering membrane inplace. Springs may also extend between the anchor and the filteringmembrane to hold the filtering membrane against the ostium. Thefiltering membrane may also be connected to a tether, elastic tether orspring and placed through the atrial appendage wall for holding thefiltering membrane against the ostium and may pull on the atrialappendage such that its volume is reduced or eliminated, trapping andisolating blood clots therein.

[0013] Part of the device may involve a suction apparatus to removeclots that are already in place. The filtering membrane placement mayrequire closure of an atrial septal defect created by the placement ofthis filter device about the appendage.

[0014] Alternatively, the filtering membrane may be held in place by acoiled spring which engages the interior wall of the atrial appendage.

[0015] The filtering membrane itself is permeable. The permeability ofthe filtering membrane allows blood to flow across, while inhibitingblood clots within the atrial appendage from exiting the atrialappendage into the bloodstream. In the case of a permeable filteringmembrane, it may eventually become infiltrated with cells so that it maybecome a “living” structure, and can develop an endothelial/endocardiallining to enable it in turn to become a non-thrombogenic surface. Itthus can develop an endothelium and with time become highlybiocompatible. It may be coated or covered with an anticoagulant orother compounds, such as, for example, heparin, or it may be treated toprevent thrombus from forming on the filtering membrane surface, toextend its patency or until it is infiltrated with cells and/or developsan endothelial covering.

[0016] The device, when implanted in the atrial appendage, may also havethe ability to perform electrical monitoring of the heart. This mayinclude two or more electrical contacts placed apart on the device, andconnected to signal conditioning circuitry for determination of cardiacfeatures such as rhythm of the atria or ventricles. Another sensor onthe device could measure pressure of the atria, atrial appendage, orventricular end diastolic pressures (left or right) through the openmitral or tricuspid valves. A suitable telemetry system would be used totelemeter this important electrical and hemodynamic informationnon-invasively outside the patient. Also, memory could be present on thedevice in order to record the information for later recovery vianoninvasive telemetry.

OBJECTS OF THE INVENTION

[0017] It is an object of the invention to provide a filter between theatrium and atrial appendage to prevent blood clots from flowingtherebetween.

[0018] It is an object of the invention to provide a filter between theatrium and atrial appendage to allow blood flow across the filter, e.g.,to reduce any hemodynamic pressure differential therebetween.

[0019] It is an object of the invention to provide a filter which ispermanently implanted between the atrium and the atrial appendage by asupport structure which substantially conforms to the contours of theostium and the interior wall of the atrial appendage.

[0020] It is an object of the invention to reduce the volume of anatrial appendage to reduce the size of the region for potential bloodstasis formation, and consequently the effective volume of the affectedatrium.

[0021] It is an object of the invention to reduce the region of staticblood in the atrial appendages and hence the thrombogenicity of theatrium.

[0022] It is an object of the invention to measure hemodynamics pressure(or flow), or electrical signals in the heart and telemeter them outsidethe body for diagnosis or monitoring.

[0023] It is an object of the invention to prevent blood clots fromforming in the atrial appendages.

[0024] It is an object of the invention to position across the ostium ofthe atrial appendage a non-thrombogenic, biocompatible surface thatprevents blood clots from forming.

[0025] It is an object of the invention to provide a permeable filteringmembrane surface which may eventually become lined with endothelial orendocardial cells.

[0026] It is an object of the invention to isolate the atrial appendagefrom the atrium proper with respect to the passage of thrombus with afiltering membrane, while allowing communication through which blood mayflow.

[0027] It is an object of the invention to minimally invasively preventblood clots from forming in the atrial appendages and escapingtherefrom.

[0028] It is an object of the invention to remove thrombi from theatrium via suction or other means.

[0029] It is an object of the invention to prevent thrombus by use ofheparin, other antithrombogenic substances, or other compounds on oreluted from the filtering membrane.

[0030] It is an object of the invention to ensure the filtering membraneis centered across or over the ostium of the atrial appendage.

[0031] It is an object of the invention to accurately place thefiltering membrane across or over the ostium of the atrial appendage.

[0032] Other objects, advantages and novel features of the presentinvention will become apparent from the following detailed descriptionof the invention when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]FIG. 1 is a partial cross sectional view of a heart showing acatheter entering the left atrial appendage using a retrograde procedurefrom the aorta in accordance with the invention.

[0034]FIG. 2 is a partial cross sectional view of a heart showing acatheter entering the left atrial appendage using a transeptal procedurefrom the femoral vein or superior vena cava in accordance with theinvention.

[0035]FIG. 3 is a partial cross sectional view of a heart showing acatheter entering the right atrial appendage from the jugular vein oroptionally from the femoral vein in accordance with the invention.

[0036]FIG. 4 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage.

[0037]FIG. 5 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage with a permeablefiltering membrane having flexible wire prongs with atraumatic bulbs tohold the filtering membrane in place and electronics built into thefiltering membrane in accordance with the invention.

[0038]FIG. 6 is similar to FIG. 5 with the atraumatic bulbs removed sothat the flexible wire prongs may puncture the atrium wall and securethe filtering membrane to the atrial appendage and a centering rim addedto the filtering membrane in accordance with the invention.

[0039]FIG. 7 is a partial cross sectional view of a portion of a heartas in FIG. 5 with a support portion between the filtering membrane andthe prongs in accordance with the invention.

[0040]FIG. 8 is similar to FIG. 7 with the atraumatic bulbs removed sothat the flexible wire prongs may puncture the atrium wall and securethe filtering membrane to the atrial appendage in accordance with theinvention.

[0041]FIG. 9 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage with a permeablefiltering membrane having a large expandable support portion to hold thefiltering membrane in place in accordance with the invention.

[0042]FIG. 10 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage having an anchorand a tether to hold the filtering membrane in place in accordance withthe invention.

[0043]FIG. 11 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage having an anchorand a spring to hold the filtering membrane in place, a centering rim onthe filtering membrane and a centering cable in accordance with theinvention.

[0044]FIG. 12 is the same as FIG. 11 with the spring filling the atriumto help hold the filtering membrane in place in accordance with theinvention.

[0045]FIG. 13 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage with the filteringmembrane adhesively being held in place in accordance with theinvention.

[0046]FIG. 14 is a partial cross sectional view of a delivery catheterhaving a disk, a spring and filtering membrane therein in accordancewith the invention.

[0047]FIG. 15 is a schematic view of a disk, spring and filteringmembrane after being expanded out of the delivery catheter of FIG. 11 inaccordance with the invention.

[0048]FIG. 16 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage having a disk, afiltering membrane and a spring therebetween in accordance with theinvention.

[0049]FIG. 17 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage shown in acollapsed position in accordance with the invention.

[0050]FIG. 18 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage having a disk, aspring, a filtering membrane and vacuum in the catheter in accordancewith the invention.

[0051]FIG. 19 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage showing anumbrella folded for entering the atrial appendage in accordance with theinvention.

[0052]FIG. 20 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage showing theumbrella opened in the atrial appendage to secure the umbrella into thewall of the atrial appendage in accordance with the invention.

[0053]FIG. 21 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage showing theumbrella and filtering membrane positioned across the ostium of theatrial appendage in accordance with the invention.

[0054]FIG. 22 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage showing a supportportion having a filtering membrane positioned across the ostium of theatrial appendage in accordance with the invention.

[0055]FIG. 23 is a partial cross sectional view of a portion of a heartshowing an atrium and its associated atrial appendage showing the atrialappendage reduced to a minimum volume by a disk and spring squeezing theappendage against a filtering membrane in accordance with the invention.

[0056]FIG. 24 is a perspective view of another embodiment of a filteringmembrane and apparatus for installing the filtering membrane inaccordance with the invention.

[0057]FIG. 25 is a sectional view of the filtering membrane andapparatus illustrated in FIG. 24, in accordance with the invention.

[0058]FIG. 26 is an enlarged view of a portion of the apparatus of FIG.25 in accordance with the invention.

[0059]FIG. 27 is a partial cross-sectional view illustrating an earlystage in the installation of the apparatus of FIG. 24, in accordancewith the invention.

[0060]FIG. 28 is a partial cross-sectional view similar to FIG. 27,illustrating a later stage in the procedure in accordance with theinvention.

[0061]FIG. 29 illustrates another embodiment of the filtering membraneand apparatus for installing the filtering membrane in accordance withthe invention.

[0062]FIG. 30 is an enlarged view of the filtering membrane andapparatus illustrated in FIG. 29 in accordance with the invention.

[0063]FIG. 31 is a planar development of the apparatus for attaching thefiltering membrane illustrated in FIGS. 29-30 in accordance with theinvention.

[0064]FIG. 32 is a planar development of the apparatus depicted in FIG.31 in an expanded configuration, in accordance with the invention.

[0065]FIG. 33 is a perspective view of the filtering membrane andapparatus for attaching the filtering membrane of FIG. 30, illustratedin an expanded configuration in accordance with the invention.

[0066]FIG. 34 is an elevational view of an embodiment of the filteringmembrane in accordance with the invention.

[0067]FIG. 35 is an elevational view of another embodiment of thefiltering membrane in accordance with the invention.

[0068]FIG. 36 is an elevational view of yet another embodiment of thefiltering membrane in accordance with the invention.

[0069]FIG. 37 is an elevational view of a further embodiment of thefiltering membrane in accordance with the invention.

[0070]FIG. 38 is a partial cross-sectional view illustrating an earlystage in the procedure of installing of the filtering membrane of FIGS.29-37 in accordance with the invention.

[0071]FIG. 39 is a partial cross-sectional view similar to FIG. 39illustrating a later stage in the procedure in accordance with theinvention.

[0072]FIG. 40 is a partial cross-sectional view similar to FIG. 39illustrating a still later stage in the procedure in accordance with theinvention.

[0073]FIG. 41 is a view similar to FIG. 38 illustrating an alternativeembodiment of the apparatus illustrated in FIGS. 29-32.

[0074]FIG. 42 is a partial cross-sectional view similar to FIG. 41illustrating a later stage in the procedure in accordance with theinvention.

[0075]FIG. 43 is a partial cross-sectional view similar to FIG. 42illustrating a still later stage in the procedure in accordance with theinvention.

[0076]FIG. 44(a) illustrates an alternative embodiment of the apparatusillustrated in FIG. 30 in accordance with the invention.

[0077]FIG. 44(b) illustrates the apparatus illustrated in FIG. 44(a) inan expanded configuration in accordance with the invention.

[0078]FIG. 45 is a view similar to FIG. 44 illustrating anotherembodiment in accordance with the invention

[0079]FIG. 46 illustrates yet another embodiment of the filteringmembrane and apparatus for attaching the filtering membrane inaccordance with the invention.

[0080]FIG. 47 is an elevational view taken from direction 47 of FIG. 41in accordance with the invention.

[0081]FIG. 48 is elevational view taken from direction 48 of FIG. 41 inaccordance with the invention.

[0082]FIG. 49 is a sectional view illustrating the apparatus of FIG. 46along with additional apparatus in accordance with the invention.

[0083]FIG. 50 is a partial cross-sectional view illustrating a firstinstalled configuration of the apparatus of FIG. 46 in accordance withthe invention.

[0084]FIG. 51 is a partial cross-sectional view similar to FIG. 50illustrating a second installed configuration of the apparatus of FIG.46 in accordance with the invention.

[0085]FIG. 52 is a partial cross-sectional view illustrating anotherembodiment of the apparatus in accordance with the invention.

[0086]FIG. 53 illustrates yet another embodiment of the apparatus inaccordance with the invention.

[0087]FIG. 54 is an end view of the apparatus of FIG. 53 in accordancewith the invention.

[0088]FIG. 55 illustrates additional apparatus for installing theapparatus of FIG. 53 in accordance with the invention.

[0089]FIG. 56 is an enlarged sectional view of the apparatus of FIG. 53and FIG. 55 in a compacted configuration, in accordance with theinvention.

[0090]FIG. 57 is a partial cross-sectional view of the apparatus of FIG.56 illustrating an early stage in the procedure in accordance with theinvention.

[0091]FIG. 58 is a partial cross-sectional view similar to FIG. 57illustrating a later stage in the procedure in accordance with theinvention.

[0092]FIG. 59 illustrates a further embodiment of the apparatus inaccordance with the invention.

[0093]FIG. 60 is an end view of the apparatus of FIG. 59 in accordancewith the invention.

[0094]FIG. 61 illustrates a still further embodiment of the apparatus inaccordance with the invention.

[0095]FIG. 62 illustrates additional apparatus for use with theapparatus of FIGS. 59-61 in accordance with the invention.

[0096]FIG. 63 is an enlarged sectional view of the apparatus of FIG. 59in accordance with the invention.

[0097]FIG. 64 is a partial cross-sectional view of the apparatus of FIG.63 illustrating an early stage in the procedure in accordance with theinvention.

[0098]FIG. 65 is a partial cross-sectional view similar to FIG. 64illustrating a later stage in the procedure in accordance with theinvention.

[0099]FIG. 66 illustrates yet another embodiment of the apparatus inaccordance with the invention.

[0100]FIG. 67 is an end view of the apparatus of FIG. 66 in accordancewith the invention.

[0101]FIG. 68 illustrates additional apparatus for use with theapparatus of FIGS. 66-67 in accordance with the invention.

[0102]FIG. 69 is an enlarged sectional view of the apparatus of FIGS. 66and 68 in accordance with the invention.

[0103]FIG. 70 is a partial cross-sectional view of the apparatus of FIG.66 illustrating an early stage in the procedure in accordance with theinvention.

[0104]FIG. 71 is a partial cross-sectional view similar to FIG. 70illustrating a later stage in the procedure in accordance with theinvention.

[0105]FIG. 72 illustrates another embodiment of the apparatus inaccordance with the invention.

[0106]FIG. 73 illustrates yet another embodiment of the apparatus inaccordance with the invention.

[0107]FIG. 74 is a partial cross-sectional view of the apparatus of FIG.72 illustrating an early stage in the procedure in accordance with theinvention.

[0108]FIG. 75 is a partial cross-sectional view similar to FIG. 74illustrating a later stage in the procedure in accordance with theinvention.

[0109]FIG. 76 illustrates yet another embodiment of the apparatus inaccordance with the invention.

[0110]FIG. 77 is a distal end view of the apparatus of FIG. 76 inaccordance with the invention.

[0111]FIG. 78 is an enlarged sectional view of additional apparatus foruse with the apparatus of FIGS. 76-77 in accordance with the invention.

[0112]FIG. 79 is a partial cross-sectional view of the apparatus ofFIGS. 76-77 illustrating an early stage in the procedure in accordancewith the invention.

[0113]FIG. 80 is a partial cross-sectional view similar to FIG. 79illustrating a later stage in the procedure in accordance with theinvention.

[0114]FIG. 81 illustrates a further embodiment of the apparatus inaccordance with the invention.

[0115]FIG. 82 is a distal end view of the apparatus of FIG. 81 inaccordance with the invention.

[0116]FIG. 83 is an enlarged sectional view of additional apparatus foruse with the apparatus of FIGS. 81-82 in accordance with the invention.

[0117]FIG. 84 is a partial cross-sectional view of the apparatus ofFIGS. 81-82 illustrating an early stage in the procedure in accordancewith the invention.

[0118]FIG. 85 is a partial cross-sectional view similar to FIG. 84illustrating a later stage in the procedure in accordance with theinvention.

[0119]FIG. 86 is a partial cross-sectional view similar to FIG. 85illustrating a still later stage in the procedure in accordance with theinvention.

[0120]FIG. 87 is a sectional view of a proximal portion of anotherembodiment in accordance with the invention.

[0121]FIG. 88 is an enlarged sectional view of a distal portion of theembodiment illustrated in FIG. 87 in accordance with the invention.

[0122]FIG. 89 is a perspective view of the embodiment illustrated inFIG. 88 in accordance with the invention.

[0123]FIG. 90 is a sectional view of an early stage of a procedure inaccordance with the invention.

[0124]FIG. 91 is a sectional view similar to FIG. 90, illustrating afurther stage in a procedure in accordance with the invention.

[0125]FIG. 92 is a sectional view similar to FIG. 91, illustrating alater stage in a procedure in accordance with the invention.

[0126]FIG. 93 is a sectional view similar to FIG. 92 at reduced scale,illustrating a later stage in a procedure in accordance with theinvention.

[0127]FIG. 94 is a sectional view similar to FIG. 93, illustratinganother embodiment in accordance with the invention.

[0128]FIG. 95 is a sectional view similar to FIG. 93, illustrating yetanother embodiment in accordance with the invention.

[0129]FIG. 96 is a sectional view similar to FIG. 93, illustrating stillanother embodiment in accordance with the invention.

[0130]FIG. 97 is a sectional view similar to FIG. 93, illustrating afurther embodiment in accordance with the invention.

[0131]FIG. 98 is a sectional view similar to FIG. 88(b), illustratinganother embodiment in accordance with the invention.

[0132]FIG. 99 is a sectional view similar to FIG. 98, illustrating alater stage in a procedure in accordance with the invention.

[0133]FIG. 100 is a sectional view similar to FIG. 99, illustrating astill later stage in a procedure in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0134] Although atrial fibrillation may result in the pooling of bloodin the left atrial appendage and the majority of use of the invention isanticipated to be for the left atrial appendage, the invention may alsobe used on the right atrial appendage and in general for placementacross any aperture in the body in which blood is permitted to flowtherethrough or therefrom but in which blood clots are substantiallyprevented from escaping from the atrial appendage and entering into thebloodstream.

[0135] As shown in FIG. 4, a thrombus, blood clot, or emboli 30(collectively referred to as a thrombus) may occur from pooling of bloodin the left atrial appendage 13 due to poor circulation of blood thereinwhen the patient experiences atrial fibrillation. When blood pools inthe left atrial appendage 13, thrombus 30 can accumulate therein, buildupon itself, and propagate out from the left atrial appendage 13 intothe left atrium 11, thus leaving the heart and entering the bloodstream. Once in the bloodstream, such thrombus can block blood flow tothe heart, brain, other organs, or peripheral vessels if it becomeslodged in the arteries thereof. Heart attack, a stroke, or ischemia mayresult.

[0136] To prevent thrombus 30 from forming in the left atrial appendage13, or to prevent thrombus formed therein from leaving and entering theblood stream which may cause a heart attack, a stroke or ischemia, afiltering membrane 40 is permanently placed across the ostium 20 of theatrial appendage 13. The filtering membrane 40 can be made ofbicompatible materials, such as, for example, ePFTE (e.g., Gortex®),polyester (e.g., Dacron®), PTFE (e.g., Teflon®), silicone, urethane,metal fibers, or other biocompatible polymers.

[0137] The filtering membrane 40 is a permeable filtering membrane,having pore sizes ranging from about 50 to about 400 microns. It is alsocontemplated that the pores may also be larger or smaller as indicatedby the circumstances, provided such pores substantially inhibit thrombusfrom passing therethrough. The open area of the filtering membrane ispreferably at least 20% of the overall surface area, although a range ofabout 25-60% may be preferred. The structure of the filtering membraneis preferably a two-dimensional screen, a cellular matrix, a woven ornon-woven mesh, or the like. The filtering membrane may also be apermeable metal or a metal mesh of fine fibers. The filtering membranemay be coated or covered with an anticoagulant, such as heparin, oranother compound, or treated to provide antithromogenic properties.

[0138] The porosity of the filtering membrane, described above, allowsblood to flow therethrough while blocking or inhibiting the passage ofthrombus, clots, or emboli formed within the atrial appendage fromentering the atrium of the heart and, eventually, the patient'sbloodstream.

[0139] The characteristic of allowing the flow of blood through thefiltering membrane provides several advantages. For example, the leftatrial appendage inherently contracts during normal cardiac function toforce blood through the heart. These contractions result in blood flowthrough the ostium of the left atrial appendage. Allowing blood flowthrough the filtering membrane substantially reduces any pressuregradient that may exist between the appendage and the atrium.

[0140] The reduction of the pressure gradient may be helpful to thepatient during recovery from the implantation of the filtering membranestructure in the atrial appendage. More particularly, the heart is ableto more gradually adapt to the presence of the filtering membrane whenblood is permitted to flow through the membrane, and consequentlythrough the ostium of the left atrial appendage.

[0141] The filtering function also reduces the risk of leakage about theperiphery of the filtering membrane, or of dislodgement of the filteringmembrane that may result from the exertion of pressure against thesurface of the filtering membrane. Allowing the blood flow across thefiltering membrane may relieve this pressure, sufficiently and in acontrolled manner, to reduce such leakage or dislodgement.

[0142] Tissue ingrowth may provide additional securement of thefiltering membrane to the ostium. More particularly, the growth oftissue may occur along the outer periphery of the filtering membrane orsupporting structure adjacent the ostium. This tissue growth, incooperation with the pressure relief provided by the permeablestructure, may provide additional means of reducing leakage about theperiphery of the filtering membrane. Tissue growth may eventually coveradditional surface area of the filtering membrane.

[0143] The filtering membrane 40 placed across or over the ostium 20should be antithrombotic. In order to make the filtering membraneantithrombotic, heparin or other anticoagulants or antiplatelet agentsmay be used on the filtering membrane 40.

[0144] When permeable filtering membranes 40 are used, an ingrowth ofcells may eventually cover the filtering membrane with endothelialcells. The endothelial cells present a smooth cellular wall covering thefiltering membrane which prevents thrombosis from occurring at thefiltering membrane.

[0145] The permeable filtering membrane 40 is permanently implantedacross the ostium and retained in position by a support structureattached to the filtering membrane. As will be described herein, suchpermanent placement is achieved by aspects of the support structurewhich, for example, may engage and/or pierce the wall of the atrialappendage. Alternatively, such permanent placement may be achieved bythe support structure which expands to engage either the ostium and/orthe interior wall of the atrial appendage. Furthermore, the supportstructure may be configured to conform to the unique configuration ofthe ostium and/or the interior wall of the atrial appendage, and thefiltering membrane held in position by the support structure to conformto the ostium.

[0146]FIGS. 1 and 2 show a cross section of a human heart showing athrombus 30 in the left atrial appendage 13. The figures also show theatrial appendage ostium 20 which is to have a filtering membrane 40placed over it to prevent the thrombus 30 from escaping out of theatrial appendage 13 into the left atrium 11 and thus into the bloodstream, which could cause a stroke, a heart attack or ischemia.

[0147]FIG. 3 shows a cross section of a human heart showing a thrombus30 in the right atrial appendage 23. The right atrial appendage 23 canbe treated in the same manner as the left atrial appendage 13.

[0148]FIG. 4 shows a cross section of the left atrium 11, the ostium 20and the left atrial appendage 13 having a thrombus 30 therein.

[0149]FIG. 5 shows a first embodiment of the invention having thepermeable filtering membrane 40 and a plurality of flexible prongs 50which may be made from a shape memory alloy, such as Nitinol®, forretaining a predisposed shape. The prongs 50 may be atraumatic so thatthey do not perforate the left atrial appendage 13. The prongs 50 mayhave atraumatic bulbs 55 on their tips so that the tips of the prongs 50will not perforate the left atrial appendage 13. Nitinol® has theproperty of being able to be placed in a catheter in a compactconfiguration and then expanded when released from the catheter to apredetermined memory shape. The shape selected may be for the prongs 50to curve around the lip of the ostium 20 and then hug the sides of theleft atrial appendage 13. In this manner the filtering membrane 40allows blood to flow through the ostium 20 but which blocks orsubstantially inhibits thrombus 30, clots or emboli from leaving theleft atrial appendage 13 and entering the atrium, and eventually, thebloodstream of the patient.

[0150] The filtering membrane 40 is self centering across or over theostium 20 of the left atrial appendage 13, by placing the prongs 50 in acircle around the filtering membrane 40 such that the prongs 50 fitagainst the wall of the left atrial appendage 13 of or within the lumenof the ostium 20 to center the filtering membrane 40 across or over theostium 20. The filtering membrane 40 may also be centered by a centeringrim 65 (see FIG. 6) attached to the back (appendage) side of thefiltering membrane 40 that protrudes into the ostium 20 for centering.The centering rim 65 has a diameter of less than the diameter of thefiltering membrane 40. The centering means may also consist of a seriesof centering cables 66 (see FIG. 11) which attach to a spring 90 ortether 85 from the centering rim 65 or the filtering membrane 40, toassure that centering occurs with placement.

[0151] Optionally electronics, such as sensors 300 and chips 310, builtinto the filtering membrane may be used to provide data abouthemodynamic pressure, flow rates, temperature, heart rates, andelectrical signals in the heart. When the filtering membrane is placedin the left atrial appendage 13 the sensors 300 may measure pressures inthe atria or atrial appendage. The sensors may also measure ventricularend diastolic pressures through the open mitral or cuspid valves. Otherinformation about the heart may be gathered such as noise fromaccelerometers to detect leakage, valve efficiency, activity levels ofthe patient and other noise related data. The sensors 300 may also beblood oxygen sensors. The chip 310 may use telemetry to transmit theinformation gathered by the sensors 300 and processed or stored by thechip 310 to receiving devices to aid in the treatment of the patient.

[0152] In FIG. 6 the protective bulbs 55 are removed from the flexibleprongs 50 of FIG. 5 such that flexible prongs 50 puncture the walls ofthe left atrial appendage 13 and secure the filtering membrane 40 inplace. The flexible prongs 50 may penetrate into the atrial appendagewall or extend through the atrial appendage wall. The prongs may havebarbed ends 51 to prevent the prongs from withdrawing from the atrialappendage wall.

[0153] As described above, filtering membrane 40 has a permeablestructure which allows blood to flow therethrough but which blocks orsubstantially inhibits thrombus, clots or emboli from entering theatrium, and eventually, the bloodstream of the patient. The filteringmembrane 40 has centering rim 65 attached for centering the filteringmembrane in the ostium 20 and marker 320 in the filtering membrane 40for observing the position of the filtering membrane while it is beinginserted. The marker may be used for x-ray or ultrasound observation.

[0154] Although Nitinol® was cited above as a type of shape memory alloyprong material which can be used, any type memory alloy may be used.Such alloys tend to have a temperature induced phase change which willcause the material to have a preferred configuration when heated above acertain transition temperature. Other metals which may be used as prongsinclude corrosion resistant spring metals such as Elgiloy® or springtempered steel.

[0155] Another embodiment of the invention is shown in FIG. 7. It issimilar to the embodiment shown in FIG. 5. The embodiment in FIG. 7 hasa support structure 60 attached to the filtering membrane 40 forexpanding in the ostium 20 helping to secure the filtering membrane 40thereto. The prongs 50 operate in the same manner as in FIG. 5 huggingthe inner walls of the left atrial membrane 13 to secure the filteringmembrane 40 across the ostium 20. As described above, filtering membrane40 has a permeable structure which allows blood to flow therethrough butwhich blocks or substantially inhibits thrombus, clots or emboli fromentering the atrium, and eventually, the bloodstream of the patient. Thesupport structure 60 may also be made from Nitinol®, Elgiloy® or anotherexpandable spring loaded or balloon expandable material.

[0156] The filtering membrane 40 may be self centering across or overthe ostium 20 of the left 13 atrial appendage, by placing the supportstructure 50 into the ostium wherein the support structure plugs theostium with the filtering membrane 40 centered in the support structure.Further the prongs 50 fit against the wall of the left atrial appendage13 of or within the lumen of the ostium 20 to center the filteringmembrane 40 across or over the ostium 20.

[0157] In FIG. 8 the protective bulbs 55 are removed from the flexibleprongs 50 of FIG. 7 such that flexible prongs 50 puncture the walls ofthe left atrial appendage 13 and secure the filtering membrane 40 inplace. The flexible prongs 50 may penetrate into the atrial appendagewall or extend through the atrial appendage wall. The prongs may havebarbed ends 51 to prevent the prongs from withdrawing from the atrialappendage wall. As described above, filtering membrane 40 has apermeable structure which allows blood to flow therethrough but whichblocks or substantially inhibits thrombus, clots or emboli from enteringthe atrium, and eventually, the bloodstream of the patient.

[0158] In the embodiment shown in FIG. 9 a larger expandable supportstructure 70 is used to both engage the sides of the ostium 20 and hugthe inside walls of the left atrial appendage 13. Again the supportstructure may be made of Nitinol®, Elgiloy® or other material which maybe delivered in a catheter and expanded to the proper size and shape tosecurely hold the filtering membrane 40 across or over the ostium 20which allows blood to flow through filtering membrane 40 but whichblocks or substantially inhibits thrombus 30, clots or emboli fromentering the atrium, and eventually, the bloodstream of the patient.

[0159]FIG. 10 shows another embodiment of the invention wherein thefiltering membrane 40 is secured across the ostium 20 by means of ananchor 80 which is driven into or through the wall of the left atrialappendage 13 and secured therein by the surface area of the anchor sothat it will not pull out of or through the wall of the left atrialappendage 13 or cause embolism from the left atrial appendage 13. Atether 85 is attached to the anchor 80 and to the filtering membrane 40to secure the filtering membrane 40 snuggly against the ostium 20.Filtering membrane 40 has a permeable structure which permits unclottedblood to flow through the filtering membrane. A contrast medium 270,such as radiographic contrast or a similar substance, may be introducedinto the left atrial appendage 13 by injection through a catheter afterthe filtering membrane 40 is in place. The device delivery catheteritself may have a port for this injection. The port may also be used toinject the contrast medium 270 that can be immediately visualized, andexamined for diagnostic purposes. In prior art devices, the introductionof the contrast medium 270 into the left atrial appendage 30 mayincrease the volume of fluid within the appendage and, consequently, thehemodynamic pressure exerted against the walls of the atrial appendageand against any membrane or structure that may be used to occlude theatrial appendage. The filtering membrane 40 allows blood and contrastmedium 270 to flow therethrough, and therefore may equalize hemodynamicpressure between the atrium and the left atrial appendage 30 in acontrolled manner. The contrast medium may be used with any of theembodiments of the invention.

[0160]FIG. 11 shows another embodiment of the invention whereinfiltering membrane 40 has a spiral spring 90 in addition to the anchor80. The spiral spring 90 can be used in conjunction with or separatelyfrom the tether 85 to pull the filtering membrane 40 against the ostium20. Although a spiral spring 90 has been shown in FIG. 11 the shape usedmay be oval, cylindrical, oblong, or other shape to connect the anchor80 to the filtering membrane 40. In another embodiment shown in FIG. 12the spiral spring 90 may fill the volume of the left atrial appendage 13securing the filtering membrane 40 to the ostium 20. The spiral spring90 filling the left atrial appendage 13 may also have an anchor 80 andtether 85 to help secure the filtering membrane 40 to the ostium 20.Alternatively centering rim 65 may be used as shown in FIG. 11 to centerthe filtering membrane 40 over ostium 20 of left atrial appendage 13.Centering cables 66 connected to spring 90 and either filtering membrane40 or centering rim 65 may also be used to center the filtering membrane40 across or over the ostium 20.

[0161]FIG. 13 shows yet another means of securing the filtering membrane40 across or over the ostium 20. In this embodiment filtering membrane40 is directly attached to the ostium 20 by an adhesive 100.

[0162]FIG. 14 shows a delivery catheter 125 containing a collapsedpermeable filtering membrane 40 and a collapsed disk 130 connected tothe permeable filtering membrane 40 by a spring 90 on catheter 21. Thedisk 130 may be made of a flexible woven metal or a flexible woven metalwith a thin permeable polymer sandwiched inside. Disk 130 may also be apolymer weave. The disk 130 is flexible and compresses or folds so itfits into the delivery catheter 125 and expands to its desired shapeafter release from the delivery catheter 125. Similarly, filteringmembrane 40 compresses or folds to fit into the delivery catheter 125and expands to its desired shape after release. FIG. 15 shows thepermeable filtering membrane 40, disk 130 and spring 90 from FIG. 14 inan expanded configuration outside of the delivery catheter 125.

[0163]FIG. 15 shows the spring 90 connecting the permeable filteringmembrane 40 and the disk 130 for urging them together. In otherembodiments an elastic tether or a tether with teeth and a pawl on thepermeable filtering membrane 40 to form a ratchet can also be used topull the permeable filtering membrane 40 and the disk 130 together.

[0164]FIG. 16 shows the device of FIG. 15 applied to the left atrialappendage 13 having thrombus 30. After the device is applied, the spring90 pulls the disk 130 toward the permeable filtering membrane 40,collapsing the left atrial appendage 13 and trapping the thrombus 30therein as shown in FIG. 17.

[0165]FIG. 18 shows an alternate embodiment of the device in FIGS. 16and 17 wherein the catheter 21 is equipped with a vacuum 140 for suckingout blood and thrombosis 30 found in the left atrial appendage 13. Thevacuum 140 will help collapse the left atrial appendage 13 such thatspring 90 need not be as large as in FIG. 16.

[0166] FIGS. 19-21 show another embodiment of the invention using anumbrella principle for securing the filtering membrane 40 against theostium 20. FIG. 19 shows closed umbrella struts 160 entering the ostium20 of left atrial appendage 13. The filtering membrane 40 is somedistance back from the umbrella struts 160 at the bottom of the range ofteeth 195 on pole 170. FIG. 20 shows the umbrella struts inside of theleft atrial appendage 13 with the struts 160 open. Umbrella openingstructure 175 on pole 170 pushes the struts out to the umbrella openposition. The umbrella opening structure 175 can be pushed to the openposition or have a spring loaded mechanism to push the struts 160 to theopen position. The ends of the umbrella struts 160 engage the leftatrial appendage wall around the ostium 20 and prevent the umbrella frombeing withdrawn from the left atrial appendage 13. The ends of theumbrella struts 160 that engage the atrial appendage wall may be bluntedor have bulbs on the tips or have padding so as not to puncture the leftatrial appendage 13. FIG. 21 shows the filtering membrane 40 drawn upagainst the ostium 20 by ratcheting the filtering membrane along pole170. The pawl mechanism 200 engages teeth 195 on pole 170 and is movedforward to snugly position the filtering membrane 40 across the ostium20.

[0167]FIG. 22 shows a support structure 260 applied to the ostium 20 ofleft atrial appendage 13. The support structure 260 expands afterleaving a delivery catheter such that the wall of the support structuresecures the support structure by pressure to the ostium 20. Filteringmembrane 240 folds or is compressed into the delivery catheter andexpands as the support structure 260 expands and lodges in the ostium 20of the left atrial appendage 13.

[0168]FIG. 23 shows the left atrial appendage 13 compressed such thatthe volume of the atrial appendage is reduced to almost nothing. Withthe volume reduced the atrial appendage will not have a large volume ofblood which can produce a thrombus. In the embodiment shown disk 130 andspring 90 pull the left atrial appendage 13 toward filtering membrane40. Although FIG. 23 shows the use of a disk 130 and spring 90 to act onthe left appendage, any method to reduce the volume of the atrialappendage as much as possible may be used.

[0169] As shown in FIG. 23 the filtering membrane 40 is much larger thanthe ostium 20. The oversized filtering membrane 40 may alternatively beused in all embodiments to ensure that the ostium 20 is completelycovered. The filtering membrane 40 has a permeable structure whichallows blood to flow therethrough, but which blocks or substantiallyinhibits thrombus, clots or emboli from entering the atrium, andeventually, the bloodstream of the patient.

[0170] FIGS. 24-28 show another embodiment of the invention wherein thefiltering membrane 40 is retained in position across the ostium 20 by anexpandable structure, such as balloon structure 402. As illustrated inFIG. 25, balloon structure 402 may be manufactured from polymericmaterials or similar materials known in the art. Tube 404 communicateswith the internal cavity of balloon structure 402 for introducing salineor other appropriate fluid into the balloon structure 402. Filteringmembrane 40 is attached to tube 404 in any appropriate manner, such asadhesive, sutures, or other means, and is provided with an aperture 406which permits access to an end portion of tube 404, which acts as aballoon introduction port 408 to allow the introduction of fluid intothe balloon structure 402.

[0171]FIG. 24 also illustrates a structure for introducing fluid intothe balloon structure 402, such as catheter apparatus 410. Catheterapparatus 410 includes an outlet port 412 at its distal end portion forejecting fluid from the catheter apparatus 410. Outlet port 412 may beconnected to the balloon introduction port 408, which in turncommunicates with the internal lumen of tube 404 and the interior ofballoon structure 402.

[0172]FIG. 25 illustrates the filtering membrane 40, the balloonstructure 402, the tube 404, together with the catheter 410 attached tothe tube 404, in a compacted configuration within a delivery tube 422.More particularly, balloon structure 402 is in its collapsed state andfiltering membrane 40 is flexible and compressed or folded to fit intothe delivery tube 422. Filtering membrane 40 is designed to expand intoa disc-like shape after release from tube 422. FIG. 26 illustrates thecertain structures pertinent to the interconnection of catheter 410 withtube 404. More particularly, outlet port 412 of catheter 410 may beprovided with narrow tube 424 which is received within balloonintroduction port 408 and maintains a valve 426 in an open position whenoutlet port 412 is connected to inlet port 408. When outlet port 412 isremoved from balloon introduction port 408, valve 426 may close toprevent fluid from leaving balloon structure 402, as shown in FIG. 26.

[0173] Delivery tube 422 may be introduced into the venous or arterialsystem at an appropriate location, and advanced to into the atrium ofthe heart with appropriate steering and visualization apparatus (notshown).

[0174]FIG. 27 illustrates a later stage in the installation procedurewherein the filtering membrane 40, the balloon structure 402, the tube404, and the catheter 410 have been advanced from the delivery tube 422(not shown in FIG. 27). The balloon structure 402 is positioned withinthe left atrial appendage 13 such that the filtering membrane 40 ispositioned about the ostium 20. Fluid is subsequently introduced intothe catheter 410 which passes through tube 404 to expand the balloonstructure 402, as illustrated in FIG. 28. The balloon structure 402expands within the atrial appendage 13 and secures the filteringmembrane 40 in position. The valve mechanism 426 (not shown in FIG. 28)of balloon introduction port 408 prevents the fluid from passing out ofthe balloon structure 402 when the catheter 410 is detached from theballoon port 408 and subsequently removed from the atrium. As describedabove, filtering membrane 40 has a permeable structure which allowsblood to flow therethrough but which blocks or substantially inhibitsthrombi, clots or emboli from exiting the atrial appendage 13, andentering the bloodstream of the patient.

[0175] FIGS. 29-40 illustrate yet another embodiment for attaching thefiltering membrane across the ostium 20 of the left atrial appendage 13.FIG. 29 illustrates the filtering membrane 40, the attachment apparatus440 for securing the filtering membrane 40 across the ostium 20 of theatrial appendage 13, and catheter apparatus 442 for installing theattachment apparatus 440 and filtering membrane 40. As FIG. 30illustrates, attachment apparatus 440 and filtering membrane 40 may beinitially in a compacted configuration. Attachment apparatus 440 ispreferably an expandable tubular apparatus having an initial diameter444 of about 1-3 mm and an initial length 446 of about 0.5-6 cm.Attachment apparatus is preferably manufactured from a flexible materialsuch as stainless steel, nitinol, nylon, polyester, PET, orpolyethylene.

[0176] Filtering membrane 40 is attached to attachment apparatus 440 atthe proximal end thereof, in a loosely fitted, somewhat conicalconfiguration and defines a central opening 448, which allows thecatheter 450 of catheter apparatus 442 to pass through membrane 40, aswill be described in greater detail herein. Alternatively, filteringmembrane 40 may also cover a greater portion of the length 446 of theattachment apparatus 440, or filtering membrane 40 may cover the entireattachment apparatus 440 in a substantially sock-like fashion. Filteringmembrane 40 may be fabricated from a material that also has elasticcharacteristics which may expand from a first size to a second size.

[0177] Catheter 450 supplies expansion fluid, such as saline or contrastmedium, into expandable structure, such as balloon structure 452, whichis positioned within the interior lumen of attachment apparatus 440 inorder to radially expand attachment apparatus 440 when it is positionedwithin the atrial appendage 13. Balloon structure 452 may include adistal, atraumatic tip portion 454, e.g., a flexible helical coil orsoft plastic tip.

[0178]FIGS. 31 and 32 illustrate planar developments of attachmentapparatus 440. The structure of attachment apparatus 440 preferablyallows the length 446 of the apparatus in its initial configuration(FIG. 31) to remain substantially constant with respect to the length456 in its expanded configuration (FIG. 32). In order to achieve thisexpansion while maintaining substantially constant length, attachmentapparatus 440 is provided with a configuration having several serpentinesegments 458, 460, and 462. Adjacent serpentine segments areinterconnected by a plurality of longitudinal struts, e.g., rings 457and 460 are interconnected by struts 464 and rings 460 and 462 areinterconnected by struts 466. A plurality of U-shaped members 470 at thedistal end portion of apparatus 440 provide an attachment point for thefiltering membrane 40.

[0179]FIG. 33 illustrates attachment member 440 in an expandedconfiguration, wherein length 456 remains substantially constant withrespect to the length 446 of the configuration illustrated in FIG. 30.Diameter 472 is substantially larger than diameter 444 (FIG. 30) inorder to secure filtering membrane 40 with the atrial appendage 13, aswill be described herein.

[0180] FIGS. 34-37 illustrate several embodiments of the filteringmembrane 40. As described above, catheter 450 passes through opening 458in filtering membrane 40 in order to supply expansion fluid toexpandable balloon structure 452. After balloon structure 452 hasexpanded the attachment apparatus 440 to the expanded configurationillustrated in FIG. 33, it may be necessary to remove balloon structure452 by passing the balloon structure 452 proximally through filteringmembrane 40, and more particularly, through opening 458. The embodimentsof filtering membrane 40 illustrated in FIGS. 34-37 may facilitate thepassage of balloon structure 452, or other interventional devicestherethrough.

[0181]FIG. 34 illustrates filtering membrane 40 a having a compositeconstruction comprising filtering section 474 a and elastic section 476a. The filtering section 474 a is fabricated from a filtering materialthat provides the function of filtering the blood to allow the blood topass therethrough while blocking or substantially inhibiting the passageof clots, thrombus or emboli therethrough, as described above. Theelastic section 476 a is fabricated from an elastic material, e.g.,silicone, urethane or other similar material, that stretches to enlargeopening 458 a to allow the balloon structure 452 or other interventiondevices, such as, e.g., wires, catheters or the like, to passtherethrough and to subsequently return to its initial size. The initialsize of aperture 458 a provides similar characteristic to inhibit clots,thrombus or emboli from passing through 458 a as filtering material offiltering section 474 a. In this configuration, elastic material 476 aextends substantially across the entire diameter 472 a of the filteringmembrane 40 a.

[0182] Filtering membrane 40 b (FIG. 35) is constructed with a filteringsection 474 b (i.e., the same material as filtering section 474 a) andan elastic section 476 b (i.e., the same elastic material as elasticsection 476 a). In filtering membrane 40 b, the filtering section 474 bsubstantially concentrically surrounds the elastic section 476 b. Theelastic section 476 b is provided with an opening 458 b that expands toallow the balloon structure 452 or other interventional devices to passtherethrough and to return to initial size in order to providesubstantially the same characteristic of inhibiting the passage ofthrombus, clots and emboli from passing therethrough as the filteringmaterial of the filtering section 474 b.

[0183] Filtering membrane 40 c (FIG. 36) is constructed with a filteringsection 474 c (i.e., the same material as filtering section 474 a) andan elastic section 476 c (i.e., the same elastic material as elasticsection 476 a). In filtering membrane 40 c, the filtering section 474 csubstantially concentrically surrounds an elastic section, such assubstantially elliptical section 476 c. The elastic section 476 c isprovided with an aperture, such as a slit 458 c that expands to allowthe balloon structure 452 or other interventional devices to passtherethrough and to return to initial size to provide substantially thesame characteristic of inhibiting the passage of thrombus, clots andemboli from passing therethrough as the filtering material of thefaltering section 474 b.

[0184] Filtering membrane 40 d (FIG. 37) may be fabricated from the samematerial as filtering section 474 a, above, in several sections, such assections 475 d and 477 d, which overlap at region 479 d to form anopening therethrough for balloon structure 452 or other interventionaldevices. It is further contemplated that three or more sections offiltering material may be used in an overlapping configuration, in amanner similar to, for example, the “aperture” configuration of anoptical device. The balloon structure 452 may be passed through theopening between sections 475 d and 477 d. After the balloon structure452 is removed, the overlapping structure substantially closes theopening and provides substantially the same characteristic of inhibitingthe passage of thrombus, clots and emboli from passing therethrough asthe filtering material of the filtering sections 475 d and 477 d.

[0185] FIGS. 38-40 illustrate the procedure for installing attachmentapparatus 440 and filtering membrane 40 in the atrial appendage 13. Inan initial step (FIG. 38), balloon structure 452, along with attachmentapparatus 440 are inserted into the atrial appendage 13 in its initial,compact configuration. In FIG. 39, expansion fluid is passed throughcatheter 450 and exits through port 453 to fill the interior of balloonstructure 452. Balloon structure 452 expands, thereby radially enlargingattachment apparatus 440, as described with respect to FIGS. 31-33,above. As illustrated in FIG. 40, attachment apparatus engages theinterior of the atrial appendage 13, thereby securing filtering membrane40 in position across the ostium 20. Balloon structure 452 may beremoved from the atrial appendage 13 by returning the balloon structure452 to its initial compact configuration (e.g., by draining theexpansion fluid therefrom) and withdrawing the balloon structureproximally through opening 458. As described above with respect to FIGS.34-37, the filtering membrane may be fabricated with an elastic portionwhich expands to permit the withdrawal of the balloon structuretherethrough, and which subsequently reduces in size to inhibit thepassage of thrombi, clots and emboli therethrough into the atrium. Thecatheter structure 442 may be subsequently removed from the patient.Alternatively, the balloon structure 452 may remain within the atrialappendage 13 following expansion of attachment apparatus 440 andsubsequent return of the balloon structure 452 to its initial compactconfiguration. For example, catheter 450 may be detachable from balloonstructure 452 in a manner similar to the configuration of catheter 410and tube 404 (FIG. 26).

[0186] FIGS. 41-43 illustrate another embodiment of the invention.Attachment apparatus 460 and balloon apparatus 462 are substantially thesame as attachment apparatus 440 and balloon apparatus 452, describedhereinabove, with the differences noted below. Attachment apparatus 460may be provided with a plurality of engagement members 464, such asprongs, hooks, or the like, in order to engage and/or pierce the wall ofthe atrial appendage to provide additional securement of the attachmentapparatus 460. Balloon structure 452 may be used in connection withattachment apparatus 460. Alternatively, balloon structure 462 may beprovided having a distal end portion which is configured to expand to agreater extent than the proximal portion thereof (FIG. 42). This greaterexpansion of the balloon structure 462 provides additional force in thearea of the engagement members 464 to drive them into the wall of theatrial appendage 13 (FIG. 43).

[0187] FIGS. 44-45 illustrate additional embodiments of expandablestructures for radially enlarging the attachment apparatus 440 (or 460)within the atrial appendage. Instead of, or in addition to balloonstructures (such as balloon structure 452), it is also contemplated thatmechanical expansion structures may be particularly useful. FIGS.44(a)-(b) illustrate a mechanical expansion structure 472 which may beused to radially expand attachment apparatus 440. As shown in FIG.44(a), mechanical expansion structure 472 may have a compactconfiguration wherein a plurality of contact members 474 define adiameter 476 that enables the structure to be inserted within theattachment apparatus 440. As illustrated in FIG. 44(b), mechanicalexpansion structure 472 also has an expanded configuration, whereincontact members 474 are further spaced apart to define a larger diameter477 which radially enlarges the attachment apparatus to theconfiguration illustrated in FIGS. 32-33 and 39-40. A linkageconfiguration may include linkage members 478 and sleeve 479. Sleeve 479is provided with internal threading (not shown) which engages externalthreading 480 on a portion of drive screw 481. Angular rotation of drivescrew 481 (as indicated by the arrow) provides longitudinal movement ofsleeve 479 which cooperates with linkage members 478 to controllablymove the contact members 474 between the compact and expandedconfigurations.

[0188]FIG. 45 illustrates mechanical expansion structure 482, which issubstantially identical to mechanical expansion structure 472. Sleeve489 interacts with linkage members 478 to controllably move contactmembers 474, as described above with respect to sleeve 479. Sleeve 489is longitudinally slidable with respect to elongated member 491. Alocking structure (not shown) may also be provided to fix the positionof sleeve 489 (and thus contact members 474) with respect to elongatedmember 491.

[0189] Mechanical expansion structures 472 and 482 may remain in theatrial appendage 13 following the expansion of attachment apparatus 440(or 460). A portion of the drive screw 481 or elongated member 491 maybe detachable from the expansion structures 472 or 482, respectively(not shown). Alternatively, apparatus substantially similar tomechanical expansion structures 472/482 may be useful as supportingstructures for filtering membrane 40. According to this embodiment,filtering membrane 40 may be attached to an end portion of structure472/482, e.g., by attaching filtering membrane 40 to end portions ofcontact members 474 or by substantially enclosing contact members 474and linkage members 478. The structure 472/482 may be positioned in theatrial appendage 13 and expanded as described above, such that filteringmembrane 40 extends across the ostium 20 to allow blood to passtherethrough while inhibiting the passage of thrombus through thefiltering membrane 40. Drive screw 481 or elongated member 491 may besubsequently detached from the apparatus 472/482.

[0190] FIGS. 46-48 illustrate another embodiment of the invention.Filtering membrane 40 may be installed in the atrial appendage 13 andheld therein by attachment apparatus 500, which preferably consists of apair of flexible wire portions 502 a and 502 b, which are preferablyconstructed of a material such as nitinol or Elgiloy or stainless steeland having a wire diameter of approximately 0.005 to 0.020 inch. Eachwire portion 502 a/502 b may include a curved portion 504 a/504 b, apair of support members 506 a/506 b and a plurality of engagementmembers 508. The curved portions 504 a/504 b define a substantiallyclosed portion for mounting the filtering membrane 40. The filteringmembrane 40 is attached with sutures, adhesive, or other appropriatemeans. The engagement members 508 are configured to engage the interiorof the atrial appendage 13 to secure the filtering membrane 40 inposition across the ostium 20, as will be described herein. Theengagement members 508 may be provided with atraumatic end portions 510.

[0191]FIG. 49 illustrates attachment apparatus 500 and filteringmembrane 40 in a compacted configuration for installation in the atrialappendage 13. Preferably, a delivery catheter apparatus 520 is used tointroduce the attachment apparatus 500 and filtering membrane 40 to theatrial appendage. The curved portions 504 a/504 b are deflectedproximally toward parallelism with the longitudinal axis of the catheter520, and the engagement members 508 are deflected distally towardparallelism with the longitudinal axis. An inner member 522 is slidablyreceived within the interior of catheter 520 and may be moved relativelylongitudinally with respect to catheter apparatus 520 in order to deployand install the attachment apparatus 500 and filtering membrane 40.

[0192] FIGS. 50-52 illustrated several options for installing thefiltering membrane across the ostium 20. As illustrated in FIG. 50, thecurved portions 504 a/504 b are positioned within the walls of theostium 20 itself. The engagement members 508 provide additional supportby engaging the interior of the atrial appendage. Alternatively, thecurved portions 504 a/504 b are positioned outside the ostium within theatrium. Engagement members 508 retain the filtering membrane 40 inposition. According to yet another alternative embodiment, engagementmember 508 are provided with sharpened barb end portions 512 whichengage and/or pierce the wall of the atrial appendage to secure thefiltering membrane in position (FIG. 52).

[0193] FIGS. 53-54 illustrate another embodiment of the invention.Attachment apparatus 600 provides a plurality of strut wires 620, e.g.,six to 12 strut wires, that extend radially outward from a support ring604. The strut wires 602 may be constructed from an alloy, such asnitinol, having shape memory characteristics. The support ring 604maintains the strut wires 602 in the proper configuration and may bemade of radiopaque materials, such as, e.g., platinum to providefluoroscopic imaging of the device position. The support ring 604 isadjacent the proximal end portion 606 of the apparatus 600, and thestrut wires 602 extend distally therefrom toward the distal end portion608. The strut wires may be provided with barbs 610 or other methods forattachment to the interior of the atrial appendage. The proximal portionof the struts 602 provide a bulb shape to conform to the ostium and/orthe internal wall of the atrial appendage.

[0194] The filtering membrane 40 is attached to strut wires 602 adjacentthe proximal portion 606 and provides the characteristics describedabove, wherein blood is allowed to pass through the filtering membrane40, but thrombi, clots, and emboli are inhibited from passingtherethrough. The filtering membrane 40 may be connected to the strutwires 602 using adhesive, sutures, encapsulation or other means.

[0195] FIGS. 55-56 illustrate apparatus for delivering and installingthe attachment apparatus 600 and filtering membrane 40. The catheterapparatus 620 includes an outer sheath 622 and an inner member 624slidably received within the interior of outer sheath 622. The outersheath 622 and inner member 624 may be fabricated from materials, suchas polymers, that are sufficiently flexible to negotiate the anatomy,yet sufficiently rigid for relative longitudinal movement to deploy andposition the attachment apparatus 600. Inner member 624 may have adistal end portion 626 and a shoulder portion 638. Support ring 604 issized to provide a slide fit over the distal portion 626, and is engagedby the shoulder portion 608. The aperture in support ring 604 issufficiently small to inhibit clots from passing through.(Alternatively, the aperture in support ring is provided with an elasticmaterial such as elastic section 476 b illustrated in FIG. 35 to preventthe passage of clots therethrough.) When positioned about distal endportion 626, strut wires 602 are deflected distally toward parallelismwith the longitudinal axis of the catheter device 622 and retained inthe deflected configuration by the outer sheath 622. In order to deploythe attachment apparatus 600, the outer sheath 622 is movedlongitudinally relative to the inner member 626. The shoulder portion628 retains the attachment apparatus 600 in position. Upon retraction ofthe outer sheath 622, the shape memory characteristics of the strutwires 602 causes the apparatus to return to a shape approximating thatof FIG. 53.

[0196] FIGS. 57-58 illustrate the installation of attachment apparatus600 and filtering membrane 40 in greater detail. As illustrated in FIG.57, the catheter device 620 is advanced partially within the atrialappendage 13. The outer sheath 622 may be retracted proximally, whichpermits the strut wires 602 to extend radially outwardly. The physicianmay use the radiopaque characteristics of the ring 604 in order toproperly position the ring 604 within the ostium 20. Further proximalretraction of the outer sheath 622 allows the strut wires 602 to extendfurther radially outward to engage the interior of the atrial appendage13 (FIG. 58). The barbs 610 may engage and/or pierce the wall of theatrial appendage to provide increased stability of the attachmentapparatus 600. The filtering membrane 40 is consequently positionedacross the ostium 20 in order to allow blood to pass through thefiltering membrane, while substantially inhibiting thrombi, clots, andemboli from exiting the atrial appendage 13.

[0197] FIGS. 59-60 illustrate another embodiment of the invention.Attachment apparatus 650 provides a first plurality of strut wires 652that extend distally and radially outward from a support ring 654 towardthe distal end portion 656 of the attachment apparatus 650, and a secondplurality of strut wires 658 that extend proximally and radially outwardfrom support ring 654 toward the proximal end portion 660. The strutwires 652/658 may be constructed from an alloy, similar to material usedfor strut wires 602, above. The support ring 654 maintains the strutwires 652/658 in the proper configuration and is substantially similarto support ring 604, above. The strut wires 652 may be provided withbarbs 662 or other methods for attachment to the interior of the atrialappendage. The struts 652/658 are configured to engage the walls of theostium on the inner and outside sides thereof, respectively.

[0198] The strut wires 658 may serve as a membrane mounting structure.The filtering membrane 40 is attached to strut wires 658 and providesthe characteristics described above, wherein blood is allowed to passthrough the filtering membrane 40, but thrombi, clots, and emboli areinhibited from passing therethrough. The filtering membrane 40 may beconnected to the strut wires 602 using adhesive, sutures, encapsulationor other means.

[0199] Another embodiment of the invention is illustrated in FIG. 61.Attachment apparatus 670 is constructed of braided or woven meshmaterial rather than the strut wires 652/658 described with respect toFIGS. 59-60. The distal portion 672 is configured to engage the wall ofthe atrial appendage adjacent the inner portion of the ostium, and theproximal portion 676 is configured to engage the outer portion of theostium, and the neck portion 674 is disposed therebetween. The braidedor woven self-expanded mesh material of attachment apparatus 670 hassimilar filtering characteristics as filtering membrane 40, oralternatively, a filtering membrane is attached to the mesh material toprovide those characteristics.

[0200] FIGS. 62-63 illustrate apparatus for delivering and installingthe attachment apparatus 650 and filtering membrane 40 and/or attachmentapparatus 670. The catheter apparatus 620 is described above withrespect to FIG. 55. Strut wires 652 of apparatus 650 (or distal portions672 of apparatus 670) are deflected distally toward parallelism with thelongitudinal axis of the catheter device 620 and retained in thedeflected configuration by the outer sheath 622. Similarly, strut wires658 (or proximal portions 676) are deflected proximally towardparallelism with the longitudinal axis and retained in thisconfiguration by the outer sheath 622. In order to deploy the attachmentapparatus 600, the outer sheath 622 is moved longitudinally relative tothe inner member 626. The shoulder portion 628 retains the attachmentapparatus 650/670 in position. Upon retraction of the outer sheath 622,the shape memory characteristics of the strut wires 652/658 (or portions672/676) cause the apparatus to return to a shape approximating that ofFIG. 59 (or FIG. 61).

[0201] FIGS. 64-65 illustrate the installation of attachment apparatus650/670 and filtering membrane 40 in greater detail. As illustrated inFIG. 64, the catheter device 622 is advanced partially within the atrialappendage 13. The outer sheath 622 may be retracted proximally, whichpermits the strut wires 652 to extend radially outwardly. The physicianmay use the radiopaque characteristics of the ring 654 in order toproperly position the ring 654 within the ostium 20. Further proximalretraction of the outer sheath 622 allows the distal strut wires 652 andthe proximal strut wires 658 to extend radially outward and engage theinterior of the atrial appendage 13 (FIG. 65). The barbs 662 may engageand/or pierce the wall of the atrial appendage to provide increasedstability of the attachment apparatus 600. The filtering membrane 40 isconsequently positioned across the ostium 20 in order to allow blood topass through the filtering membrane, while substantially inhibitingthrombi, clots, and emboli from exiting the atrial appendage 13.

[0202] FIGS. 66-67 illustrate yet another embodiment of the invention.Attachment apparatus 700 provides a plurality of strut wires 702 thatextend radially outward from a support ring 704. A first portion 706 ofeach strut wire 702 extends towards the proximal end portion 708 of theattachment apparatus 700, and a second portion 710 of each strut wire702 extends towards the distal end portion 712. The distal portion 710of each strut wire 702 may be provided with a sharpened barb tip 714 orother methods for attachment to the interior of the atrial appendage.The strut wires 702 are constructed from an alloy, similar to materialused for strut wires 602, above. The support ring 704 maintains thestrut wires 702 in the proper configuration and is substantially similarto support ring 604, above. The proximal portions 706 and distalportions 710 of strut wires 702 are configured to engage the walls ofthe ostium on the outer and inner sides thereof, respectively.

[0203] The filtering membrane 40 is attached to proximal portions 706 ofstrut wires 702 and provides the characteristic described above, whereinblood is allowed to pass through the filtering membrane 40, but thrombi,clots, and emboli are inhibited from passing therethrough. The filteringmembrane 40 may be connected to the strut wires 702 using adhesive,sutures, encapsulation or other means.

[0204] FIGS. 68-69 illustrate apparatus for delivering and installingthe attachment apparatus 700 and filtering membrane 40. The catheterapparatus 620 is described above with respect to FIG. 55. Strut wires702 are deflected towards parallelism with the longitudinal axis of thecatheter device 620 and retained in the deflected configuration by theouter sheath 622. In order to deploy the attachment apparatus 700, theouter sheath 622 is moved longitudinally relative to the inner member626. The shoulder portion 628 retains the attachment apparatus 700 inposition. Upon retraction of the outer sheath 622, the shape memorycharacteristics of the strut wires 702 causes the apparatus to resumethe shape approximating that of FIG. 66.

[0205] FIGS. 70-71 illustrate the installation of attachment apparatus700 and filtering membrane 40 in greater detail. As illustrated in FIG.70, the catheter device 622 is advanced partially within the atrialappendage 13. The outer sheath 622 may be retracted proximally, whichpermits the distal portions 710 of strut wires 702 to extend radiallyoutwardly. Further proximal retraction of the outer sheath 622 allowsthe distal portions 710 to engage the interior of the atrial appendage13 and the proximal portions 706 to engage the outer portion of theostium 20 (FIG. 71). The barbs 714 may engage and/or pierce the wall ofthe atrial appendage to provide increased stability of the attachmentapparatus 700. The filtering membrane 40 is consequently positionedacross the ostium 20 in order to allow blood to pass through thefiltering membrane, while substantially inhibiting thrombi, clots, andemboli from exiting the atrial appendage 13.

[0206] FIGS. 72-73 illustrate additional embodiments of the invention.Attachment apparatus 750 includes a plurality of strut wires 752 thatextend radially outward and distally from a support member 754 towardsthe distal end portion 756. Each strut wire 752 may be provided with asharpened barb tip 758 or other methods for attachment to the interiorof the atrial appendage. The strut wires 702 are constructed from analloy, similar to the material used for strut wires 602, above. Thesupport member 754 maintains the strut wires 752 in the desiredconfiguration.

[0207] The proximal end portion of support member 754 supports a curvedmembrane mounting structure 760 that defines a substantially closedcurve. The filtering membrane 40 is attached to membrane mountingstructure 760 and provides the characteristic described above, whereinblood is allowed to pass through the filtering membrane 40, but thrombi,clots, and emboli are inhibited from passing therethrough. The filteringmembrane 40 may be connected to the membrane mounting structure 760using adhesive, sutures, encapsulation or other means.

[0208] The attachment apparatus 770, illustrated in FIG. 73 issubstantially identical to attachment apparatus 750, with thedifferences noted herein. For example, the proximal end portion ofsupport member 754 supports a membrane mounting structure 772 having aspiral configuration. The filtering membrane 40 is attached to spiralmounting structure 772 substantially as described above with respect tomembrane mounting structure 760, above. The spiral configuration may,e.g., assist in reducing the mounting structure to a compactedconfiguration during installation.

[0209] FIGS. 74-75 illustrate the installation of attachment apparatus750 (or 770) and filtering membrane 40 in the atrial appendage 13.Catheter apparatus 780 is provided for delivering and installing theattachment apparatus 750 and filtering membrane 40. The catheterapparatus 780 is similar to catheter apparatus 620 described above withrespect to FIG. 55. Catheter apparatus 780 includes an outer sheath 782and an inner member 784. Inner member 784 preferably has an engagementsurface 785 on a distal end portion thereof. During installation, strutwires 752 are deflected towards parallelism with the longitudinal axisof the catheter device 780 and retained in the deflected configurationby the outer sheath 782 (not shown in FIG. 74). Similarly, the membranemounting portion 760 (or 772) is folded, rolled or otherwise compactedinside outer sheath 782 as illustrated in FIG. 74.

[0210] In order to deploy the attachment apparatus 750, the catheterdevice 780 is advanced partially within the atrial appendage 13. Theouter sheath 782 may be retracted proximally, which permits the strutwires 752 to extend radially outwardly due to its shape memorycharacteristics, as shown. The inner member 784 retains the attachmentapparatus 750 in position.

[0211] As illustrated in FIG. 75, further proximal retraction of theouter sheath 782 allows the strut wires 752 to extend radially outwardand engage the interior of the atrial appendage. The barbs 758 mayengage and/or pierce the wall of the atrial appendage to provideincreased stability of the attachment apparatus 700. The membranemounting structure 760 (or 772) is likewise permitted to return to itsdisc-like configuration, such that filtering membrane 40 is positionedacross the ostium 20 in order to allow blood to pass through thefiltering membrane, while substantially inhibiting thrombi, clots, andemboli from exiting the atrial appendage 13.

[0212] FIGS. 76-80 illustrate another embodiment of the invention.Attachment apparatus 800 has a braided or woven mesh portion 802 and aplurality of engagement members 804. Woven portion 802 defines aproximal portion 806 and distal portion 810. Woven portion 802 isfabricated from a material having shape memory characteristics, such asnitinol or an elastic polymeric material. Woven portion 802 isfabricated such that proximal portions 806 and distal portions 810 arenormally biased to extend radially outward from support rings 812 and814, respectively. The configuration of the woven portion 802illustrated in FIGS. 76-77 is intended to conform to the ostium of theatrial appendage. The braided or woven self-expanding mesh material ofwoven portion 802 also has similar filtering characteristics asfiltering membrane 40, which allows blood to pass therethrough whilesubstantially inhibiting the passage of thrombus. Alternatively, afiltering membrane is attached to the woven material to provide thesecharacteristics.

[0213] A plurality of engagement members 804 extend distally fromsupport ring 814. The end portions of engagement members 804 may beprovided with a barbed configuration to engage and/or pierce the wall ofthe atrial appendage and retain the engagement member in the wall.Engagement members 804 are similarly constructed from material havingshape memory characteristics, such as nitinol.

[0214]FIG. 78 illustrates apparatus for delivering and installing theattachment apparatus 800 and filtering membrane 40. The catheterapparatus 820 is similar to that described above with respect tocatheter apparatus 520 (FIG. 55). Inner member 825 may include a guidewire 824 and shoulder portion 826. Guide wire 824 may extend throughsupport rings 812 and 814. When apparatus 800 is positioned on catheterapparatus 820, woven portion 802 is deflected towards parallelism withthe longitudinal axis of the catheter device 820 and retained in thedeflected configuration by the outer sheath 822. Similarly, theengagement members 804 are deflected towards parallelism and retained insuch position by the outer sheath 822. In order to deploy the attachmentapparatus 800, the outer sheath 822 is moved longitudinally relative tothe inner member 626, while the shoulder portion 826 retains theattachment apparatus 800 in position. Upon retraction of the outersheath 822, the shape memory characteristics of the woven portion 802cause the apparatus to return to the shape approximating that of FIGS.76-77.

[0215] As illustrated in FIG. 79, attachment apparatus 800 is partiallyinserted into the atrial appendage 13. Guide member 824 may be used toassist in the placement of attachment apparatus 800 with the atrialappendage by providing visual or tactile indication to the physician.Outer sheath 822 may be retracted proximally, which allows engagementmembers 804 to deflect radially outwardly, thereby engaging the interiorwall of the atrial appendage. The barbs 805 may engage and/or pierce thewall of the atrial appendage to provide increased stability of theattachment apparatus 800. Outer sheath 822 may be further retractedproximally, thereby exposing woven portion 802, which expands radiallyoutwardly to conform to the ostium 20 of the atrial appendage. Thefiltering membrane 40 (or the woven portion 802 having such filteringcharacteristics) is consequently positioned across the ostium 20 inorder to allow blood to pass through the filtering membrane, whilesubstantially inhibiting thrombi, clots, and emboli from exiting theatrial appendage 13.

[0216] FIGS. 81-86 illustrate another embodiment of the invention.Attachment apparatus 850 has a support structure including a pluralityof struts 852 and an anchor structure 854. Struts 852 each define aproximal portion 856 and a distal portion 858. Struts 852 are fabricatedfrom a material having shape memory characteristics, such as nitinol oran elastic polymeric material. Struts are fabricated such that proximalportions 856 and distal portions 858 are normally biased to extendradially outwardly. The configuration of the struts 852 illustrated inFIG. 78 conforms to the ostium of the atrial appendage when installed,as described herein. Filtering membrane 40 substantially covers struts802, and provides the filtering characteristics described above, whichallows blood to pass therethrough but substantially inhibits the passageof clots, thrombus, or emboli. Anchor structure 854 extends distallyfrom struts 802 and includes a stylet tip 860 and two or more barbs 862.

[0217]FIG. 83 illustrates apparatus for delivering and installing theattachment apparatus 850 and filtering membrane 40. The catheterapparatus 880 is similar to that described above with respect tocatheter apparatus 780 (FIG. 74). An outer sheath 882 and inner member884 having an engagement surface 888 are provided. Struts 852 aredeflected towards parallelism with the longitudinal axis of the catheterdevice 880 and retained in the deflected configuration by the outersheath 882. Barbs 862 of the anchor portion are deflected towardsparallelism by the distal nose portion 883 of the outer sheath 882. Inorder to deploy the attachment apparatus 850, the inner member 884 ismoved longitudinally relative to the outer sheath 882. The engagementsurface 888 of the inner member 884 urges the attachment apparatus 850out of the outer sheath 882. Upon deployment from the outer sheath 882,the shape memory characteristics of the material causes the apparatus toreturn to the shape approximating that of FIG. 81.

[0218] As illustrated in FIG. 84, attachment apparatus 800 is partiallyinserted into the atrial appendage 13. The stylet tip 860 is exposedfrom outer sheath 882 and pierces the wall of the atrial appendage. Thedistal nose portion 883 of the outer sheath 882 retains the barbs 862towards parallelism with the longitudinal axis, thereby enabling thesebarbs 862 to pass through the wall of the atrial appendage. Once thebarbs 862 have passed through the wall, the barbs 862 may deflectradially outwardly, thereby preventing the anchor structure from beingwithdrawn proximally back through the wall (FIG. 85).

[0219] As illustrated in FIG. 86, outer sheath 882 may be retractedproximally, thereby exposing struts 852, which expand radially outwardlyto conform to the ostium 20 of the atrial appendage. The filteringmembrane 40 (or the woven portion 802 having such filteringcharacteristics) is consequently positioned across the ostium 20 inorder to allow blood to pass through the filtering membrane, whilesubstantially inhibiting thrombi, clots, and emboli from exiting theatrial appendage 13.

[0220] Another embodiment is illustrated in FIGS. 87 and 88 and isdenoted generally by reference number 900. This embodiment may comprisea deployment apparatus 910 for installing attachment apparatus 912,thereby securing the filtering membrane 40 across the ostium 20 of theatrial appendage 13.

[0221] Deployment apparatus 910 has a proximal handle portion 914 and anelongated shaft portion 916. Elongated shaft portion 916 is preferablyflexible for introducing the apparatus in the patient's vascular systemand advancing the attachment apparatus into the atrium of the heart andadjacent the atrial appendage 13. Proximal handle portion 910 maycomprise a body portion 918, which supports the elongated shaft portion916 (consisting of a drive tube 926 and an outer tube 936). Body portion918 also supports a rotation knob 920 and a longitudinal slide 922. Therotation knob 920 is configured to rotate angularly about thelongitudinal axis of the body portion 918 (as indicated by arrow 924).Drive tube 926 is connected to rotation knob 920, such that rotation ofthe rotation knob 920 also rotates drive tube 926 about the longitudinalaxis of (as indicated by arrow 928). Drive tube 926 may be provided withan internal lumen 930 to permit a guide wire (not shown) to be used inconnection with this procedure.

[0222] Longitudinal slide control 922 may be slidable within a slot 932in the body portion 918 (as indicated by arrow 934). Slide control 922is connected to outer tube 936, and is longitudinally slidable therewith(as indicated by arrow 938).

[0223] As FIG. 88 illustrates, attachment apparatus 912 is configuredfor attachment to the distal end of elongated shaft portion 910.Attachment apparatus 912 is initially in the compacted configurationshown in FIGS. 88 and 89. As FIG. 89 illustrates, attachment apparatus912 may comprise an outer portion 941 having an initially cylindricalconfiguration with a diameter 940 of about 2.0 mm and an initial length942 of about 2.5 cm. Outer portion 941 is preferably manufactured from aflexible material such as stainless steel, nitinol, or Elgiloy®. Outerportion 941 has a plurality of longitudinal struts 946 defined elongatedslots 944. Longitudinal struts 946 are configured to enlarge radiallyoutwardly to engage the ostium of the left atrial appendage, as will bedescribed herein.

[0224] Filtering membrane 40 is attached to outer portion 941 preferablyabout the proximal portions of the longitudinal struts 946 and has aninitially cylindrical configuration. Filtering membrane 40 may befabricated in a tapered configured and folded about the outer portion941. Alternatively, membrane 40 may be fabricated from a material thathas elastic characteristics which allow expansion from the initialcylindrical configuration to a substantially tapered configuration (see,FIG. 90).

[0225] With reference to FIG. 88, attachment apparatus 912 may alsocomprise a male threaded member 948 defining outer threads 950, and afemale threaded member 952 defining inner threads 953 cooperating withouter threads 950. Male threaded member 948 is longitudinally fixedadjacent the proximal portion of outer portion 941, and female threadedmember 952 is longitudinally fixed adjacent the distal portion of outerportion 914. As male threaded member 948 and female threaded member 952are longitudinally approximated by relative angular rotationtherebetween, the medial portion of the longitudinal struts 946 deflectradially outwardly in a toggle-like fashion (as illustrated in FIG. 90).The cooperating threaded configuration of members 948 and 952 providesadditional resistance against the longitudinal struts 946 returning tothe compacted configuration of FIG. 89. A plurality of locking tabs 954are provided adjacent the proximal portion of attachment apparatus 912,as will described herein.

[0226] The proximal end portion of elongated shaft portion 910 isconfigured for attachment to, and subsequent removal from, theattachment apparatus 912. More particularly, a collet 956 is attached tothe distal end of outer tube 936. Collet 956 may be provided with aplurality of apertures 959, which receive locking tabs 954 therein.Driver 958 may be attached to the distal end of drive tube 926. Driver958 preferably has a locking arrangement with respect to a longitudinalbore 960 in male threaded member 948. For example, driver 958 may have afaceted outer surface defining six planar surfaces which is received inbore 960 defining a complementary faceted surface that allows relativelongitudinal movement between driver 958 and male threaded member 948,while inhibiting relative angular rotation therebetween.

[0227] Attachment apparatus 912 is positioned at least partially withinthe atrial appendage 13 in the compacted configuration as illustrated inFIGS. 88 and 89.

[0228] A next stage in the procedure for installing the attachmentapparatus 912 and filtering membrane 40 is illustrated in FIG. 90. Oncethe physician has determined that the attachment apparatus 912 isproperly positioned, the rotation knob 920 may be rotated in thedirection indicated by arrow 924 (see, FIG. 88). Rotation of rotationknob 920 causes drive tube 926, along with driver 958, to also rotateangularly. The cooperating relationship of driver 958 within malethreaded member 948 causes male threaded member 948 to rotate angularly(as indicated by arrow 962). The outer threads 950 and inner threads 953are configured such that rotation of male threaded member 948 causeslongitudinal motion of female threaded member 952 (i.e., in thedirection indicated by arrow 964). To deploy the attachment apparatus912, the male threaded member 948 is rotated to cause the femalethreaded member 952 to move proximally, thereby deflecting thelongitudinal struts 946 radially outwardly (as indicated by arrow 966).Further rotation of the male threaded member 948 deflects thelongitudinal struts 946 radially outwardly until they engage the ostium20 or the interior wall of the atrial appendage 13.

[0229] After deployment of the attachment apparatus 912, the deploymentapparatus 910 may be detached from the attachment apparatus 912. Moreparticularly, collet 956 is moved proximally longitudinally by movinglongitudinal slider 922 proximally with respect to handle body portion918 (as indicated by arrow 970). Longitudinal movement of collet 956disengages locking tabs 954 from within apertures 959 provided on thedistal portion of collet 958. As FIG. 92 illustrates, the drive tube 926and driver 958 may be subsequently detached from the attachmentapparatus 912 by proximal movement thereof (as indicated by arrow 970).It is also contemplated that alternative means may be provided totemporarily attach the shaft portion 910 to the attachment apparatus,such as a friction fit between the various components.

[0230] As illustrated in FIG. 93, attachment apparatus 912 secures thefiltering membrane 40 across the ostium 20 of the atrial appendage 13.Filtering membrane 40 provides the filtering characteristics describedabove, which allows blood to pass therethrough but substantiallyinhibits the passage of clots, thrombus, or emboli.

[0231] FIGS. 94-97 illustrate several additional embodiments of theattachment apparatus described herein with respect to FIGS. 88-93. FIG.94 illustrates attachment apparatus 981, substantially similar toattachment apparatus 912, having one or more barbs 980 provided onlongitudinal struts 946 in order to engage the ostium 20 or the interiorwall of the atrial appendage 13. FIG. 95 illustrates attachmentapparatus 983, substantially similar to attachment apparatus 912,wherein each of the longitudinal struts 946 has a substantially straightlongitudinal section 984, which may provide improved conformity to theostium 20 of the atrial appendage 13.

[0232]FIG. 96 illustrates attachment member 985, substantially similarto attachment apparatus 912, wherein the longitudinal struts 946 haveunequal length sections 987 and 990, which may provide additionalstability and conformity to the ostium 20. FIG. 97 illustratesattachment apparatus 992, substantially similar to attachment apparatus912, wherein the longitudinal struts 946 are configured to engage theostium 20 or the interior wall of the atrial appendage 13 at a pluralityof longitudinal locations, e.g., locations 993 and 994. Thisconfiguration may be achieved by attaching a portion of the longitudinalstruts 946 to a slidable collar 995. In addition, the longitudinalstruts 946 may be provided with barbs 996, which are configured toengage the ostium 20 and the interior wall of the atrial appendage 13 ata plurality of locations.

[0233] Yet another embodiment is illustrated in FIGS. 98-100, and isdenoted by reference number 1000. Apparatus 1000 is substantiallysimilar to the apparatus 900 described above, with the differences notedherein. Attachment apparatus 1012 is substantially similar to attachmentapparatus 912. However, filtering membrane 40 may be annularly attachedto the outer portion 941 adjacent the proximal end portion thereof.Moreover, filtering membrane 40 may be separately expandable fromlongitudinal struts 946. In a preferred embodiment, filtering membrane40 is attached to an expandable membrane support frame 1040 which ispreferably fabricated from a material having shape-memorycharacteristics, such as nitinol, and is self-expanding to radiallyoutwardly disposed configuration.

[0234] Deployment apparatus 1010 is substantially similar to deploymentapparatus 910. However, deployment apparatus 1010 may also comprisesheath 1030 which is sized to fit coaxially about the membrane 40 andthe outer tube 936. Sheath 1030 retains the membrane support frame 1040in a compacted configuration substantially parallel with thelongitudinal axis of the apparatus. Sheath 1030 may be withdrawnproximally in order to permit the membrane support frame to expandradially outwardly.

[0235]FIG. 98 illustrates the attachment apparatus 1012 in an initial,compacted configuration. Sheath 1030 is coaxially disposed about thefiltering membrane 40 to retain the membrane support frame 1040substantially parallel with the longitudinal axis. Moreover, thecooperating threaded portions 952 and 948 are relatively positioned suchthat longitudinal struts 946 are also in the compacted, substantiallycylindrical configuration. This configuration is useful for insertingand positioning the attachment apparatus 1012 adjacent the ostium 20 ofthe atrial appendage 13.

[0236]FIG. 99 illustrates a next step in the deployment of attachmentapparatus 1012. When the attachment apparatus 1012 is positionedadjacent the ostium 20 of the atrial appendage 13, or partially disposedwithin the atrial appendage 13, the sheath 1030 may be withdrawnproximally (as indicated by arrow 1031). Withdrawal of sheath 1030permits membrane support frame 1040 to expand radially outwardly (asindicated by arrows 1041), thereby outwardly expanding filteringmembrane 40 therewith.

[0237]FIG. 100 illustrates a further step in the deployment ofattachment apparatus. Filtering membrane 40 is positioned by thephysician over the ostium 20 of the atrial appendage 13. The filteringmembrane may define an outer periphery which is larger than the size ofthe ostium 20. Filtering membrane 40 is secured in position by expandinglongitudinal struts 946 to engage the interior of the atrial appendage13 and/or the ostium 20. Expansion of the longitudinal struts 946 iseffected by rotation of the male threaded member 948 with respect to thefemale threaded member 952 by driver 958 (as described above withrespect to FIG. 90). When the attachment apparatus 912 is securelypositioned within the atrial appendage 13, the deployment apparatus 1010may be detached from the attachment apparatus 1012, substantially asdescribed above with respect to FIGS. 91-92. The filtering membrane 40is secured in position by the attachment apparatus 1012 across theostium 20. More particularly, the outer periphery of the filteringmembrane 40 may be secured in direct engagement with the atrial wallsurrounding the ostium 20.

[0238] The devices described above may be percutaneously delivered tothe left and right atrial appendages 13, 23 respectively. The devicesmay have materials in them which enhance visualization or imaging byultrasound, x-ray or other means making it easier for the device to beimplanted and accurately centered with respect to the ostium 20 of theatrial appendage 13. This may consist of small beads placedstrategically on the filtering membrane, the connecting elements, or onthe anchors. Referring to FIG. 1 catheter 21 is seen entering the heartby way of the aorta 12 to the left ventricle 16 passing through themitral valve 17 and then entering the left atrial appendage 13 to applythe permeable filtering membrane 40 in one of the embodiments asdisclosed above. In FIG. 2 the catheter 21 enters the heart from thefemoral vein, passes through the inferior vena cava 18 to the rightatrium and then passes through the fossa ovalis 19 or through the septum29 into the left atrium 11 and then approaches the left atrial appendage13 to apply the permeable filtering membrane 40 thereto. FIG. 3 showsthe catheter 21 being applied to the right atrial appendage 23. Catheter21 may enter the heart through the jugular vein 28 or the femoral veinto the inferior vena cava 18.

[0239] It is understood that the invention may be practiced withnumerous means of attaching the filtering membrane 40 across the ostium20 of the atrial appendages 13 and 23. All of the above embodimentsshown and discussed for the left atrial appendage 13 are also useable onthe right atrial appendage 23. Any combination of the attachment meanswith adhesives, prongs, cylindrical structures, anchors, disks, tethersor springs may be used. The filtering membrane may also be inside of theatrial appendages 13 and 23, or may penetrate the atrial appendage andprovide a means to securely lock the filtering membrane device intoplace. Other means of providing a filtering membrane for allowing bloodflow therethrough and substantially inhibiting blood clots from exitingout of the atrial appendages not listed herein may also be used.

[0240] Obviously, many modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically described.

What is claimed is:
 1. Apparatus for permanent placement across anostium of a left atrial appendage in a patient, comprising: a filteringmembrane configured to extend across the ostium of the left atrialappendage and having a permeable structure which allows blood to flowthrough the filtering membrane but substantially inhibits thrombus frompassing therethrough; and a support structure defining a firstconfiguration having a substantially cylindrical shape and a secondconfiguration defining a radially enlarged medial portion to permanentlyengage the interior wall of the left atrial appendage, wherein thefiltering membrane is attached to the support structure extending acrossthe ostium of the left atrial appendage.
 2. Apparatus as defined inclaim 1, wherein the support structure comprises a plurality of fingerseach having a first end portion, a second end portion, and a medialportion, and wherein the medial portion of each finger is radiallyoutwardly expanded in the second configuration.
 3. Apparatus as definedin claim 2, wherein the support structure further comprises first andsecond cooperating threaded members configured for relative angularrotation, wherein each cooperating threaded member is attached to arespective first and second end portion of each finger, and wherein thefirst and second end portions of said fingers are approximated by saidrelative angular rotation between the cooperating threaded members. 4.Apparatus as defined in claim 3, further comprising: an actuatorconfigured to expand the plurality of fingers by angularly rotating oneof the cooperating threaded members about the longitudinal axis. 5.Apparatus as defined in claim 4, wherein the actuator further comprisesan outer tube configured for releasable attachment to the supportstructure.
 6. Apparatus as defined in claim 5, wherein the supportmember comprises a tab structure and the outer tube defines an apertureat an end portion thereof, and wherein the outer tube is releasablyattached to the support member by engagement of the tab structure in theaperture.
 7. Apparatus as defined in claim 5, wherein the outer tube isreleasably attached to the support member by a frictional fit. 8.Apparatus as defined in claim 1, wherein the fingers are fabricated ofstainless steel.
 9. Apparatus as defined in claim 1, wherein the fingersare fabricated of nitinol.
 10. Apparatus as defined in claim 1, whereinthe fingers comprise a barbed portion configured to engage an interiorwall of the atrial appendage.
 11. The apparatus of claim 1 furthercomprising an actuator configured to remotely radially outwardly expandthe support structure.
 12. The apparatus of claim 11, wherein thesupport structure comprises a plurality of fingers and wherein theactuator comprises a drive member configured to expand the plurality offingers by angularly rotating one of the cooperating threaded membersabout the longitudinal axis.
 13. The apparatus of claim 1 wherein thesupport structure a membrane support frame that is radially outwardlyexpandable to engage the atrial wall surrounding the ostium, and whereinthe filtering membrane is attached to the membrane support frame toextend over the ostium of the left atrial appendage.
 14. Apparatus asdefined in claim 13, wherein the membrane support frame is fabricatedfrom a material having shape-memory characteristics.
 15. Apparatus asdefined in claim 13, wherein the membrane support frame is elasticallyexpandable.